Karen Stupples and Shi Hyun Ahn fired matching rounds of 65 to climb into a tie for second place at 11-under-par 133. Annika Sorenstam, a three-time champion of this event, posted a 68 to join Lorena Ochoa, Cristie Kerr and Catriona Matthew at 10-under-par 134.
Park set a new tournament mark with her 62 in the opening round and the 25- year-old picked up where she left off on Friday with a birdie at the par-4 first.
She ran off a string of pars before a birdie at the par-3 sixth to move to 12 under. Park faltered to a bogey at the par-5 seventh, but managed to recover with a birdie at the par-4 ninth.
As her challengers were starting to close in, Park tallied a birdie at the par-5 12th and another at the par-3 13th. Park then made it three in a row with a birdie at the par-4 14th.
'I played solid today,' said Park, who won this year's Kraft Nabisco Championship. 'I feel like I could birdie every hole on this course, the way I've been striking the ball and putting.'
Park's 129 broke the previous record of 132. Emilee Klein established the original mark in the 1996 event and Kerr matched it in 2002.
Stupples, who won this year's Women's British Open, collected her first birdie of the day at the par-4 fourth and birdied three straight starting at the par-5 seventh to make the turn at 8 under.
The 31-year-old added a birdie at the par-4 11th and reached 10 under with a birdie at the par-4 14th. Stupples then birdied the par-4 closing hole for her share of second.
Ahn torched the front side with six birdies. The 20-year-old cooled off on the inward half, but snuck in a birdie at the last to finish four shots off the lead.
Sorenstam, who is seeking her sixth victory of the season, birdied the third and added another birdie at the sixth. She then eagled the par-5 seventh and tallied a birdie at the par-5 12th to reach 11 under.
The Swede parred her next five holes, but found trouble coming in with a bogey at the 18th to finish five back.
Defending champion Sophie Gustafson carded a 70 to finish alone in eighth place at 8-under-par 136. Juli Inkster and Jeong Jang followed at 7-under-par 137 while Christina Kim was one shot further back at 6-under-par 138.
Karrie Webb and Mi Hyun Kim tied for 12th place at 4-under-par 140. Wendy Doolan and Jennifer Rosales were knotted at 3-under-par 141 and Hee-Won Han took 16th place alone at 1-under-par 143.
Se Ri Pak and Meg Mallon shared 17th place at 1-over-par 145. Amateur sensation Michelle Wie managed a 72 to come in at 2-over-par 146 while Laura Davies rounded out the elite field at 3 over par.